diff options
| -rw-r--r-- | drivers/infiniband/core/device.c | 54 | ||||
| -rw-r--r-- | include/rdma/ib_verbs.h | 3 |
2 files changed, 44 insertions, 13 deletions
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 9773145dee09..d86fbabe48d6 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -99,6 +99,12 @@ static LIST_HEAD(client_list); static DEFINE_XARRAY_FLAGS(clients, XA_FLAGS_ALLOC); static DECLARE_RWSEM(clients_rwsem); +static void ib_client_put(struct ib_client *client) +{ + if (refcount_dec_and_test(&client->uses)) + complete(&client->uses_zero); +} + /* * If client_data is registered then the corresponding client must also still * be registered. @@ -661,6 +667,14 @@ static int add_client_context(struct ib_device *device, down_write(&device->client_data_rwsem); /* + * So long as the client is registered hold both the client and device + * unregistration locks. + */ + if (!refcount_inc_not_zero(&client->uses)) + goto out_unlock; + refcount_inc(&device->refcount); + + /* * Another caller to add_client_context got here first and has already * completely initialized context. */ @@ -683,6 +697,9 @@ static int add_client_context(struct ib_device *device, return 0; out: + ib_device_put(device); + ib_client_put(client); +out_unlock: up_write(&device->client_data_rwsem); return ret; } @@ -702,7 +719,7 @@ static void remove_client_context(struct ib_device *device, client_data = xa_load(&device->client_data, client_id); xa_clear_mark(&device->client_data, client_id, CLIENT_DATA_REGISTERED); client = xa_load(&clients, client_id); - downgrade_write(&device->client_data_rwsem); + up_write(&device->client_data_rwsem); /* * Notice we cannot be holding any exclusive locks when calling the @@ -712,17 +729,13 @@ static void remove_client_context(struct ib_device *device, * * For this reason clients and drivers should not call the * unregistration functions will holdling any locks. - * - * It tempting to drop the client_data_rwsem too, but this is required - * to ensure that unregister_client does not return until all clients - * are completely unregistered, which is required to avoid module - * unloading races. */ if (client->remove) client->remove(device, client_data); xa_erase(&device->client_data, client_id); - up_read(&device->client_data_rwsem); + ib_device_put(device); + ib_client_put(client); } static int alloc_port_data(struct ib_device *device) @@ -1705,6 +1718,8 @@ int ib_register_client(struct ib_client *client) unsigned long index; int ret; + refcount_set(&client->uses, 1); + init_completion(&client->uses_zero); ret = assign_client_id(client); if (ret) return ret; @@ -1740,16 +1755,29 @@ void ib_unregister_client(struct ib_client *client) unsigned long index; down_write(&clients_rwsem); + ib_client_put(client); xa_clear_mark(&clients, client->client_id, CLIENT_REGISTERED); up_write(&clients_rwsem); + + /* We do not want to have locks while calling client->remove() */ + rcu_read_lock(); + xa_for_each (&devices, index, device) { + if (!ib_device_try_get(device)) + continue; + rcu_read_unlock(); + + remove_client_context(device, client->client_id); + + ib_device_put(device); + rcu_read_lock(); + } + rcu_read_unlock(); + /* - * Every device still known must be serialized to make sure we are - * done with the client callbacks before we return. + * remove_client_context() is not a fence, it can return even though a + * removal is ongoing. Wait until all removals are completed. */ - down_read(&devices_rwsem); - xa_for_each (&devices, index, device) - remove_client_context(device, client->client_id); - up_read(&devices_rwsem); + wait_for_completion(&client->uses_zero); down_write(&clients_rwsem); list_del(&client->list); diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index c5f8a9f17063..7b80ec822043 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -2647,6 +2647,9 @@ struct ib_client { const union ib_gid *gid, const struct sockaddr *addr, void *client_data); + + refcount_t uses; + struct completion uses_zero; struct list_head list; u32 client_id; |